2,2,4,4-Tetraalkyl-1,3-cyclobutanediol (TACD) is a cycloaliphatic compound that can be used as a diol component for making polyesters. Thermoplastics based on TACD polyester exhibit improved impact resistance owing to TACD's unique structure. TACD can also provide improved hydrolytic stability of the polyester due to its secondary hydroxyl functionality. Both of these properties are highly desirable in thermosetting coatings.
However, coatings made with TACD containing curable polyester resins where the primary mode of cross-linking is across the hydroxyl groups on the curable polyester resin are slow to cure because the secondary hydroxyl groups on the TACD moiety are slow to react under curing conditions. To the extent that a cross-linked matrix does form, it is only poorly cross-linked which manifests itself in the formation of films with poor solvent resistance. Thus, there is a need to provide TACD based curable polyester resins that are able to more rapidly cure with conventional crosslinkers, especially phenolic based cross-linkers, and provide a well cross-linked coating that has good properties.